From 95c40f41cfaf34e1c07812e93aa4b3263f9953f3 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sun, 25 Jun 2017 12:30:25 -0700 Subject: vmbus: drop unused ring_buffer_info elements The elements ring_data_start_offset and priv_write_index are not used. Signed-off-by: Stephen Hemminger Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- include/linux/hyperv.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/linux/hyperv.h') diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index b7d7bbec74e0..5e5f966bf37f 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -124,8 +124,6 @@ struct hv_ring_buffer_info { spinlock_t ring_lock; u32 ring_datasize; /* < ring_size */ - u32 ring_data_startoffset; - u32 priv_write_index; u32 priv_read_index; u32 cached_read_index; }; -- cgit v1.2.3 From 8dd45f2ab005a1f3301296059b23b03ec3dbf79b Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sun, 25 Jun 2017 12:30:26 -0700 Subject: vmbus: refactor hv_signal_on_read The function hv_signal_on_read was defined in hyperv.h and only used in one place in ring_buffer code. Clearer to just move it inline there. Signed-off-by: Stephen Hemminger Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/ring_buffer.c | 32 +++++++++++++++++++++++++++++-- include/linux/hyperv.h | 49 ------------------------------------------------ 2 files changed, 30 insertions(+), 51 deletions(-) (limited to 'include/linux/hyperv.h') diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index f29981764653..a9021f13379f 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -29,6 +29,7 @@ #include #include #include +#include #include "hyperv_vmbus.h" @@ -357,7 +358,7 @@ struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; - /* set state for later hv_signal_on_read() */ + /* set state for later hv_pkt_iter_close */ rbi->cached_read_index = rbi->ring_buffer->read_index; if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) @@ -400,6 +401,8 @@ EXPORT_SYMBOL_GPL(__hv_pkt_iter_next); void hv_pkt_iter_close(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; + u32 cur_write_sz, cached_write_sz; + u32 pending_sz; /* * Make sure all reads are done before we update the read index since @@ -409,6 +412,31 @@ void hv_pkt_iter_close(struct vmbus_channel *channel) virt_rmb(); rbi->ring_buffer->read_index = rbi->priv_read_index; - hv_signal_on_read(channel); + /* + * Issue a full memory barrier before making the signaling decision. + * Here is the reason for having this barrier: + * If the reading of the pend_sz (in this function) + * were to be reordered and read before we commit the new read + * index (in the calling function) we could + * have a problem. If the host were to set the pending_sz after we + * have sampled pending_sz and go to sleep before we commit the + * read index, we could miss sending the interrupt. Issue a full + * memory barrier to address this. + */ + virt_mb(); + + pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); + /* If the other end is not blocked on write don't bother. */ + if (pending_sz == 0) + return; + + cur_write_sz = hv_get_bytes_to_write(rbi); + + if (cur_write_sz < pending_sz) + return; + + cached_write_sz = hv_get_cached_bytes_to_write(rbi); + if (cached_write_sz < pending_sz) + vmbus_setevent(channel); } EXPORT_SYMBOL_GPL(hv_pkt_iter_close); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 5e5f966bf37f..308e1f9706bb 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -1471,55 +1471,6 @@ hv_get_ring_buffer(const struct hv_ring_buffer_info *ring_info) return ring_info->ring_buffer->buffer; } -/* - * To optimize the flow management on the send-side, - * when the sender is blocked because of lack of - * sufficient space in the ring buffer, potential the - * consumer of the ring buffer can signal the producer. - * This is controlled by the following parameters: - * - * 1. pending_send_sz: This is the size in bytes that the - * producer is trying to send. - * 2. The feature bit feat_pending_send_sz set to indicate if - * the consumer of the ring will signal when the ring - * state transitions from being full to a state where - * there is room for the producer to send the pending packet. - */ - -static inline void hv_signal_on_read(struct vmbus_channel *channel) -{ - u32 cur_write_sz, cached_write_sz; - u32 pending_sz; - struct hv_ring_buffer_info *rbi = &channel->inbound; - - /* - * Issue a full memory barrier before making the signaling decision. - * Here is the reason for having this barrier: - * If the reading of the pend_sz (in this function) - * were to be reordered and read before we commit the new read - * index (in the calling function) we could - * have a problem. If the host were to set the pending_sz after we - * have sampled pending_sz and go to sleep before we commit the - * read index, we could miss sending the interrupt. Issue a full - * memory barrier to address this. - */ - virt_mb(); - - pending_sz = READ_ONCE(rbi->ring_buffer->pending_send_sz); - /* If the other end is not blocked on write don't bother. */ - if (pending_sz == 0) - return; - - cur_write_sz = hv_get_bytes_to_write(rbi); - - if (cur_write_sz < pending_sz) - return; - - cached_write_sz = hv_get_cached_bytes_to_write(rbi); - if (cached_write_sz < pending_sz) - vmbus_setevent(channel); -} - /* * Mask off host interrupt callback notifications */ -- cgit v1.2.3 From 05d00bc94ac27d220d8a78e365d7fa3a26dcca17 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Sun, 25 Jun 2017 12:30:27 -0700 Subject: vmbus: eliminate duplicate cached index Don't need cached read index anymore now that packet iterator is used. The iterator has the original read index until the visible read_index is updated. Signed-off-by: Stephen Hemminger Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- drivers/hv/ring_buffer.c | 17 ++++------------- include/linux/hyperv.h | 14 -------------- 2 files changed, 4 insertions(+), 27 deletions(-) (limited to 'include/linux/hyperv.h') diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index a9021f13379f..b0f79526b86a 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -358,9 +358,6 @@ struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; - /* set state for later hv_pkt_iter_close */ - rbi->cached_read_index = rbi->ring_buffer->read_index; - if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) return NULL; @@ -388,10 +385,7 @@ __hv_pkt_iter_next(struct vmbus_channel *channel, rbi->priv_read_index -= dsize; /* more data? */ - if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor)) - return NULL; - else - return hv_get_ring_buffer(rbi) + rbi->priv_read_index; + return hv_pkt_iter_first(channel); } EXPORT_SYMBOL_GPL(__hv_pkt_iter_next); @@ -401,7 +395,7 @@ EXPORT_SYMBOL_GPL(__hv_pkt_iter_next); void hv_pkt_iter_close(struct vmbus_channel *channel) { struct hv_ring_buffer_info *rbi = &channel->inbound; - u32 cur_write_sz, cached_write_sz; + u32 orig_write_sz = hv_get_bytes_to_write(rbi); u32 pending_sz; /* @@ -430,13 +424,10 @@ void hv_pkt_iter_close(struct vmbus_channel *channel) if (pending_sz == 0) return; - cur_write_sz = hv_get_bytes_to_write(rbi); - - if (cur_write_sz < pending_sz) + if (hv_get_bytes_to_write(rbi) < pending_sz) return; - cached_write_sz = hv_get_cached_bytes_to_write(rbi); - if (cached_write_sz < pending_sz) + if (orig_write_sz < pending_sz) vmbus_setevent(channel); } EXPORT_SYMBOL_GPL(hv_pkt_iter_close); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 308e1f9706bb..27db4e650b8c 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -125,7 +125,6 @@ struct hv_ring_buffer_info { u32 ring_datasize; /* < ring_size */ u32 priv_read_index; - u32 cached_read_index; }; /* @@ -178,19 +177,6 @@ static inline u32 hv_get_bytes_to_write(const struct hv_ring_buffer_info *rbi) return write; } -static inline u32 hv_get_cached_bytes_to_write( - const struct hv_ring_buffer_info *rbi) -{ - u32 read_loc, write_loc, dsize, write; - - dsize = rbi->ring_datasize; - read_loc = rbi->cached_read_index; - write_loc = rbi->ring_buffer->write_index; - - write = write_loc >= read_loc ? dsize - (write_loc - read_loc) : - read_loc - write_loc; - return write; -} /* * VMBUS version is 32 bit entity broken up into * two 16 bit quantities: major_number. minor_number. -- cgit v1.2.3 From 6f3d791f300618caf82a2be0c27456edd76d5164 Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Fri, 11 Aug 2017 10:03:59 -0700 Subject: Drivers: hv: vmbus: Fix rescind handling issues This patch handles the following issues that were observed when we are handling racing channel offer message and rescind message for the same offer: 1. Since the host does not respond to messages on a rescinded channel, in the current code, we could be indefinitely blocked on the vmbus_open() call. 2. When a rescinded channel is being closed, if there is a pending interrupt on the channel, we could end up freeing the channel that the interrupt handler would run on. Signed-off-by: K. Y. Srinivasan Reviewed-by: Dexuan Cui Tested-by: Dexuan Cui Signed-off-by: Greg Kroah-Hartman --- drivers/hv/channel.c | 14 ++++++++++++++ drivers/hv/channel_mgmt.c | 29 ++++++++++++++++++++++++++--- drivers/hv/vmbus_drv.c | 3 +++ include/linux/hyperv.h | 2 ++ 4 files changed, 45 insertions(+), 3 deletions(-) (limited to 'include/linux/hyperv.h') diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index e57cc40cb768..63ac1c6a825f 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -177,6 +177,11 @@ int vmbus_open(struct vmbus_channel *newchannel, u32 send_ringbuffer_size, &vmbus_connection.chn_msg_list); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + if (newchannel->rescind) { + err = -ENODEV; + goto error_free_gpadl; + } + ret = vmbus_post_msg(open_msg, sizeof(struct vmbus_channel_open_channel), true); @@ -421,6 +426,11 @@ int vmbus_establish_gpadl(struct vmbus_channel *channel, void *kbuffer, spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + if (channel->rescind) { + ret = -ENODEV; + goto cleanup; + } + ret = vmbus_post_msg(gpadlmsg, msginfo->msgsize - sizeof(*msginfo), true); if (ret != 0) @@ -494,6 +504,10 @@ int vmbus_teardown_gpadl(struct vmbus_channel *channel, u32 gpadl_handle) list_add_tail(&info->msglistentry, &vmbus_connection.chn_msg_list); spin_unlock_irqrestore(&vmbus_connection.channelmsg_lock, flags); + + if (channel->rescind) + goto post_msg_err; + ret = vmbus_post_msg(msg, sizeof(struct vmbus_channel_gpadl_teardown), true); diff --git a/drivers/hv/channel_mgmt.c b/drivers/hv/channel_mgmt.c index 4bbb8dea4727..968af173c4c1 100644 --- a/drivers/hv/channel_mgmt.c +++ b/drivers/hv/channel_mgmt.c @@ -451,6 +451,12 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) /* Make sure this is a new offer */ mutex_lock(&vmbus_connection.channel_mutex); + /* + * Now that we have acquired the channel_mutex, + * we can release the potentially racing rescind thread. + */ + atomic_dec(&vmbus_connection.offer_in_progress); + list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { if (!uuid_le_cmp(channel->offermsg.offer.if_type, newchannel->offermsg.offer.if_type) && @@ -481,7 +487,6 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) channel->num_sc++; spin_unlock_irqrestore(&channel->lock, flags); } else { - atomic_dec(&vmbus_connection.offer_in_progress); goto err_free_chan; } } @@ -510,7 +515,6 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) if (!fnew) { if (channel->sc_creation_callback != NULL) channel->sc_creation_callback(newchannel); - atomic_dec(&vmbus_connection.offer_in_progress); return; } @@ -541,7 +545,7 @@ static void vmbus_process_offer(struct vmbus_channel *newchannel) goto err_deq_chan; } - atomic_dec(&vmbus_connection.offer_in_progress); + newchannel->probe_done = true; return; err_deq_chan: @@ -882,8 +886,27 @@ static void vmbus_onoffer_rescind(struct vmbus_channel_message_header *hdr) channel->rescind = true; spin_unlock_irqrestore(&channel->lock, flags); + /* + * Now that we have posted the rescind state, perform + * rescind related cleanup. + */ vmbus_rescind_cleanup(channel); + /* + * Now wait for offer handling to complete. + */ + while (READ_ONCE(channel->probe_done) == false) { + /* + * We wait here until any channel offer is currently + * being processed. + */ + msleep(1); + } + + /* + * At this point, the rescind handling can proceed safely. + */ + if (channel->device_obj) { if (channel->chn_rescind_callback) { channel->chn_rescind_callback(channel); diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index ed84e96715a0..43160a2eafe0 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -940,6 +940,9 @@ static void vmbus_chan_sched(struct hv_per_cpu_context *hv_cpu) if (channel->offermsg.child_relid != relid) continue; + if (channel->rescind) + continue; + switch (channel->callback_mode) { case HV_CALL_ISR: vmbus_channel_isr(channel); diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h index 27db4e650b8c..07650d0232cc 100644 --- a/include/linux/hyperv.h +++ b/include/linux/hyperv.h @@ -879,6 +879,8 @@ struct vmbus_channel { */ enum hv_numa_policy affinity_policy; + bool probe_done; + }; static inline bool is_hvsock_channel(const struct vmbus_channel *c) -- cgit v1.2.3